Improve module Command about cantoolz HOT 1 OPEN

class replay(CANModule):
    # . . .
    def do_init(self, params):
        # . . .
        self.register_command(NewCommand(prog='g', description='Enable/disable sniffing to collect CAN packets', callback=self.cmd_sniff))
        self.register_command(NewCommand(prog='p', description='Print count of loaded CAN packets', callback=self.cmd_show_count))
        new_cmd = NewCommand(prog='l', description='Load CAN packets from file', callback=self.cmd_load)
        new_cmd.add_argument('filename', help='Filename where to load the packets from')
        self.register_command(new_cmd)
        new_cmd = NewCommand(prog='r', description='Replay range from loaded CAN packets', callback=self.cmd_replay_range)
        new_cmd.add_argument('start', nargs='?', type=int, default=-1, help='Index of the first packet to replay')
        new_cmd.add_argument('end', nargs='?', type=int, default=-1, help='Index of the last packet to replay')
        self.register_command(new_cmd)
        new_cmd = NewCommand(prog='d', description='Save range of loaded CAN packets', callback=self.cmd_save_dump)
        new_cmd.add_argument('start', nargs='?', type=int, default=-1, help='Index of the first packet to save')
        new_cmd.add_argument('end', nargs='?', type=int, default=-1, help='Index of the last packet to save')
        new_cmd.add_argument('filename', nargs='?', default='replay.save', help='Filename where to store the packets')
        self.register_command(new_cmd)
        self.register_command(NewCommand(prog='c', description='Reset loaded CAN packets', callback=self.cmd_reset))
    # . . .
    def cmd_save_dump(self, start, end, filename=None):
        """Save a range of CAN messages from the loaded packets.

        :param int start: Index of the first frame to replay.
        :param int end: Index of the last frame to replay.
        :param str filename: Filename where to write the CAN frames to.
        """
        filename = filename or self.filename
        start = max(0, start)
        end = min(end, len(self.replay))
        return self.replay.save_dump(filename, start, end - start)

class CANModule:
    # . . .
        def raw_write(self, string):
        """Call the command specified in `string` and return its result. Used for direct input.

        :param str string: The full command with its parameters (e.g. 's' to stop the module)

        :returns: str -- Result of the command execution.
        """
        self.thr_block.wait(timeout=self._timeout)  # Timeout of 3 seconds
        self.thr_block.clear()
        command_name, *params = shlex.split(string)
        if command_name not in self.commands:
            raise KeyError("Module '{}' does not have the command '{}'".format(self.__class__.__name__, command_name))
        command = self.commands[command_name]
        if not command.enabled:
            ret = 'Error: command {} is disabled!'.format(command_name)
        else:
            args = vars(command.parse_args(params))
            try:
                ret = command.callback(**args)
            except Exception as e:
                ret = 'Error: {}'.format(e)
                traceback.print_exc()
        self.thr_block.set()
        return ret